﻿If a <em>Representation</em> is given being an <em>IfcProductDefinitionShape</em>, then also an <em>ObjectPlacement</em> has to be given. The <em>ObjectPlacement</em> defines the object coordinate system in which the geometric representation items of the <em>IfcProductDefinitionShape</em> are founded. 
<blockquote class="note">NOTE&nbsp; If the <em>Representation</em> of several subtypes of <em>IfcProduct</em> have the same coordinate system it is permitted to share an instance of <em>IfcObjectPlacement</em>. </blockquote>